Telephone-exchange system.



H. P. CLAUSEN. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED OCT. 29. I9I5.

INE MORRIS PEY'ERS 00,. PNU'IULITNO.. WASHING ION. D. C

UNITED sTaTEs EETEET oEErcE.

HENRY PETER CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR, BY- MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEVI YORK.

Application led October 29, 1915.

To all whom t may concern.'

Be it known that I, HENRY PETER CLAU- sEN, a citizen of the United States, residing at Mount Vernon, in the county of Vestchester and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone eX- change systems, the object being to provide a system which will facilitate the reestablishment of connections between two subscribers who have been accidentally disconnected.

In accordance with this invention, there is provided a link circuit at a regular operators position or before a special operator, which may be connected to the two lines which have been accidentally disconnected from each other, and which will not telephonically connect the two subscribers until after both have restored their receivers to the switchhooks. When the receivers have been restored to the switchhooks, ringing immediately begins upon both lines, whereupon the subscribers may then remove the receivers from the switchhooks, disconnecting the source of ringing current from the respective lines and connecting through the talking circuit of the link circuit.

The accompanying dra-wing illustrates diagrammatically apparatus wired in accordance with this invention.

A link circuit, wired as shown in the drawing, may be provided at a special operators position or at a regular operators position to suit traffic conveniences, Shown in connection with the link circuit are subscribers lines A and B connected by means of line wires 1, 2 to a line jack 3located at the central office. Associated with each subscribers line is the usual line equipment comprising a cut-O relay 4 and a line relay 5, the latter controlling a line lamp 6. The link circuit is provided with connecting plugs 7, which are adapted to be inserted into the line 'ack 3. J This invention may best be understood by describing the operation of the apparatus shown in the drawing under varying conditions, each of which will be taken up and described separately.

As stated above, this invention is espe- Specification of Letters Patent.

TELEPHONE-EXCHANGE SYSTEM.

Patented June 19, 1917.

serial No. 58,639.

cially applicable to restablishing connection between conversing parties accidentally disconnected. It may be assumed that the operator has been informed by either one or both of subscribers A and B that their conversation was interrupted and that the operator requested said subscribers to replace their receiver upon the switchhook until signaled. Thereupon, to reestablish the former connection between the parties, the operator, we will say, insertedv the plug 7 into the line jack 3 of-subscriber As line. This operation established an energizing circuit for the relay 8, which may be traced as follows: battery, coil of relay 8, ring and sleeve strand of the cord circuit, coil of relay 4, to ground. Simultaneously with'the insertion of the plug-into the jack of subscriber AsY line, the operator will perform a corresponding operation in respect to subscriber Bs line. In this case an energizing circuit will be established through relay 9 corresponding to the relay 8, which may be traced as follows: battery, coil of relay 9, ring and sleeve strand of the cord circuit, coil of relay 4, to ground. The energization of the relays 8 and 9 inonek instance effect the closure of contacts 10 and 11, thereby establishing a circuit for the relay 12 over the following path: batt-ery, contact 10, conductor 13, contact 14, coil of relay 12, contact 15, conductor 16, contact 11, to ground. As the relay 12 controls the application of ringing current to either subscriber A or Bs line, upon its actuation ringing current will be impressed upon subscriber As line over the following path: from a source of generator, coil of rclay 17, conductor 18, contact 19, conductor 20, contact 21, conductor 22, contact 23, tip strand of the cord circuit, out overthe subscriber As line and back to the ring side of the cord circuit, conductor 24, contact 25, conductors 26, 27, in'ductorium 28, to battery. At the same time subscriber As line is receiving ringing current, a similar circuit is established for sending out ringing current upon subscriber Bs line, which may be described as follows: generator, coil of relay 31, conductor 32, contact 33, conductor 34, contact 35, conductor 36, contact 37, tip side of the link circuit, through the substation and back over the ring side of said link circuit, conductor 38, contact 39, conductors 40,

4l. to battery through inductoriuin 28. .Ringing current will now be applied to both subscribers lines until interrupted by said subscribers removing the receiver from their respective switchhooks.

lt will be noted that during the time ringing current is applied, the operator will be notified of this fact by the burning of lamp 42. A circuit for this lamp was completed at the time the relay 8 was energized, which circuit may be described as follows: bat-tery, lamp 42, contact 43, conductor 44, conductor 45, contact 46, conductors 47, 48, contact 49, to ground. The relay will not be energized at this time becausel it is shunted out through the path including contact 46.

As is usual in practice, ringing current will be applied to the subscribers lines until interrupted by the removal of the receiver at the substation. Upon the removal of the receiver several things occur, one of which the ringing relay 1.7 is tripped, which may be accomplished in any well-known manner, thus opening Contact 46 which extinguishes the lamp 42 by interrupting the circuit thereof at this point. Also the open ing of contact 46 removes the short circuit about the relay 50, thus permitting its energization over a circuit which may be traced as follows: battery, lamp 42, contact fl-3, conductor 44, contact 5l, coil of relay .30, conductor 48, contact 49, to ground. T he actuation of the relay 50 closes contact which is made before contact 5l is broken. The closure of this contact establishes a locking circuit for the relay 50, which may be described as follows: battcry, inductorium 28, conductor 27, contact 52, coil of relay 50, conductor 48, contact 49, to ground. The energization of the relay 50 also removes ringing current from subscriber As line by opening its back contact 253, and completes a talking circuit by closing the tip strand of the link circuit, which is normally opened through its front contact 53.

It Will be noted that the relay was energized by the removal of the receiver from the switrhhook by subscriber A, the circuit for which may be traced as follows: battery, coil of relay 8, ring strand of the cord circuit, through the substation' A and back over the tip side of the cord circuit, contact 5B, coil of relay 55, to ground. The energization of the relay will elfect the extinguishing of the lamp The relays 8 and may be said to correspond to the ordinary supervisory relays of a cord circuit.

lWhen subscriber B responds, circuits, similar to those already descriled, will be established for removing ringing current from said subscriber Bs line. As in the fermer case, the removal of the receiver effects the tripping of the ringing relay 3l, thereby opening contact (50. The opening of contact GO causes the energization of the relay 61 by removing the short circuit thereabout, thus completing the following circuit: battery, lamp 62, contact G3, conductor 64, contact G5, coil of relay 6l, conductor 6G, contact (57, to ground. rilhe closure of contact 68 takes place before the opening of contact (S5, thereby establishing a locking circuit for the relay 61 similar' to the locking circuit. established for the relay 50. rlhis circuit may be described as follows: battery, inductorium 2S, conductor 41, contact (itl, coil of relay (ll, conductor GF, contact 6T, to ground. lt willy also be observed that the relay 70 was energized by the removal ol' the receiver at substation B over the following circuit: battery, coil of relay 9, ring strand of the cord circuit, through the substation and back over tip side of the cord circuit. contact (if), coil of relay 7l), to ground. rl`he energization of this relay causes the extinguishing of lamp G2. Connection between subscribers A and B is now restablisbed. To permit the op-I erator to listen iu, a listening key Tl is provided, being bridged across the talking strand of the link circuit in a manner well understood in practice.

Let it be assumed that at the time the operator attempted to reestablish connection between the talking parties, subscriber had his receiver removed from the switchhook at the time the plug 7 ivas inserted into the line jack This causes the relay 72 to become energized through the closure of the following circuit: battery, coil of relay S, ring strand of the link circuit through the substation and back over the tip strand of the link circuit, contact 23, conductor 22, contact 2l, conductor 20, contact T3, coil. of relay T2, to ground. The energization of this relay opened contact 14, thereby opening the energizing circuit of the rela y l2 at this point, which prevented ringing current being applied to subscriber Als line during the time he had his receiver off the switchhook since the relay 12 controls the application of said ringing cur rent. The same feature would be true if subscriber' lls receiver was removed from the switchhook when the `plug T was inserted into his line jack 3. In this instance the relay 74 would be energized over a circuit which may be traced as follows: battery, coil of relay 9, ring strand of the cord circuit, out over the line and back over the tip side of a cord circuit, contact 3T. conductor 3G, contact conductor 34, contact 75, coil of relay 74- to ground. It may be noted here that in event the plug 7 was inserted into the jack 3 of subscriber Bs line when the plug T of the opposite end of the link cir cuit was inserted. into the jack 3 of subscriber As line, and subscriber A had his receiver removed, there is a possibility of the energizing circuit for the relay 72 being destroyed through the opening of contact 73 il relay 12 responded first, since the relays 72 and l2 have their respective circuits completed simultaneously. To prevent the happening of this contingency, the relay 12 is ot the type slow in responding, which insures the immediate energization of the relay 72 and renders the relay l2 ineffective. By this arrangement it is impossible to apply ringing current to a subscribers line when the receiver is removed from the switch-hook. It will also be noted that by virtue of the locking circuits for the relays 50 and (il after either subscriber has responded, no ringing current can be impressed upon his line until the operator has withdrawn the connecting plug 7 and reinserted it into his respective line jack. The withdrawal of the plug permits the deenergization of either of these relays and the consequent closure of their back contacts 23 and 37, thus restablishing a ringing circuit. lt will further be noticed that the circuit for the' relays 72 and Til will be completed in the event the operator inserted the plug T into the line jack 3 while another plug was inserted in a multiple ack of this line.

From the above it will be apparent. that by the means provided by this invention communicat-ion may be established between two interrupted subscribers with little inconvenience to the operator or the talking parties; also that adequate supervisory means are provided to prevent any disagreeable or annoying circumstances from arising, such as ringing a party while he has a receiver removed from the switchhook.

That is claimed is:

l. A telephone exchange system comprising subscribers lines terminating at a central office, a call bell for each line, a link circuit thereat, a source of ringing current at the central office, apparatus associated with each end of the link circuit for controlling the connection of the source of ringing current to the subscribers lines to which the link circuit is connected, and means at the central oliceI controlled jointly by the two subscribers for causing the operation of said apparatus to simultaneously connect the source of ringing current to the connected lines and cause the operation of both call bells.

2. A telephone exchange system comprising two telephone lines terminating at a central oiice, a link circuit thereat connected with the two lines, a source of ringing current at the central oflice, electromagnetic switching means controlled over each line and responsive to the opening thereof, and apparatus operating upon the response of upon the denergization of the first men-.

tioned relays to connect the source of ringing current to the telephone lines.

4. A telephone exchange system comprising two telephone lines terminating at a central office, a link circuit thereat connected with the telephone lines, a source of ringing current at the central office, a relay for each end of the link circuit controlled over the respective connected telephone lines, and a third Yrelay when energized attracting its armature to connect the source of ringing current to the telephone lines, and an energizing circuit for the third relay including contacts of the iii-st mentioned relays.

5. A telephone exchange system comprising two telephone lines terminating at a central office, a link circuit thereat connected with the lines and comprising a talking conductor open at two points, a source of ringing current, a relay for each end of the link circuit controlled over the respective connected telephone lines, a third relay operating upon the denergization of the first mentioned relays to connect a source of ringing current to the two telephone lines, and a relay associated with each end of the link circuit operating upon the removal from the switchhooks of the receivers of the respective telephone lines to disconnect the source of ringing current from the respective lines and to close the breaks in the talking conductor of the link circuit.

6. A telephone exchange system comprising two telephone lines terminating at a central oiiice, a link circuit thereat connected with the telephone lines and comprising a talking conductor open at one point, a source of ringing current at the central otce, a relay associated with each end of the link circuit and controlled over the respective connected lines, a third relay operating when the first mentioned relays are denergized to connect the source of ringing current to one of the telephone lines, and apparatus operating upon the removal of the receiver of the signaled telephone line from the switchhook to disconnect the source of ringing current therefrom and to close the break in the talking conductor of the link circuit.

7. A telephone exchange system comprising two telephone lines terminating at a central oi'fice, a link circuit thereat connected with the two lines, a source of ringing current at the central ollice, electromagnetic switching means controlled over each line and responsive to the opening` thereof, apparatus operating` npon the response oi the electromagnetic switching means When both lines are open to connect the source of ringingT current to both lines, and apparatus associated with each end of the link circuit responsive to the subsequent closure of the respective connected telephone line to disconnect the source of ringing current therefrom.

8. A telephone exchange system comprising two telephone lines terminating at a eentral oilice, a link circuit thcreat connected with the tiro lines, a source of ringing' cnrrent at the central ollice, a rela)T in each end of the link circuit controlled over the respectii'e connected telephone lines, a third rela7 at the central ollice energized upon the deiincrgization of first lnei'itioned relais to connect the source ot' ringing current to the telephone lines, and n relay in each end of the link circuit responsive to the removal of the receivers of the respective telephone lines from the switchhooks to disconnect the source of ringing current from the lines.

9. A telephone exchange system comprising two telephone lines terminating at a central office, a link circuit connected with the two lines, a source of ringing current at the central otlice, a rela)7 When energized simultaneously connecting the source of ringing' current to both lines, and an energizing circuit .for the relay completed upon the opening of the two lines.

ln Witness whereof, I hereunto subscribe my naine this 26th day of October, A. D.

HENRY PETER CLUSEN.

Copies of this patent may be obtained. for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

